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-rw-r--r--arch/mips/include/asm/stackframe.h19
1 files changed, 19 insertions, 0 deletions
diff --git a/arch/mips/include/asm/stackframe.h b/arch/mips/include/asm/stackframe.h
index 3b6da3330e3..c8419129e77 100644
--- a/arch/mips/include/asm/stackframe.h
+++ b/arch/mips/include/asm/stackframe.h
@@ -121,6 +121,25 @@
.endm
#else
.macro get_saved_sp /* Uniprocessor variation */
+#ifdef CONFIG_CPU_LOONGSON2F
+ /*
+ * Clear BTB (branch target buffer), forbid RAS (return address
+ * stack) to workaround the Out-of-order Issue in Loongson2F
+ * via its diagnostic register.
+ */
+ move k0, ra
+ jal 1f
+ nop
+1: jal 1f
+ nop
+1: jal 1f
+ nop
+1: jal 1f
+ nop
+1: move ra, k0
+ li k0, 3
+ mtc0 k0, $22
+#endif /* CONFIG_CPU_LOONGSON2F */
#if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32)
lui k1, %hi(kernelsp)
#else